An ink-jet printing apparatus ejects ink (print liquids) droplets from an ejection opening of a print head to be attached on a printed material, thus printing an image thereon. Since the ink droplet contains a solvent such as water or an organic solvent, removal of the solvent is performed from the ink for settling the ink on the printed material. For removing the solvent from the ink, for example, a heater is used.
An image forming device disclosed in Patent Literature 1 is provided with a drying unit including a drying heater which heats a print paper to vaporize the solvent in the ink, a water component collecting device for collecting the vaporized solvent, and a collecting tank for reserving the collected solvent. The water component collecting device is a compressor type dehumidification system or a desiccant dehumidification system.